1. Field of the Invention
The present invention relates generally to plasma assisted methods for processing integrated circuit layers. More particularly, the present invention relates to plasma assisted methods for processing integrated circuit layers, which plasma assisted methods provide limited contaminant particle deposition upon those integrated circuit layers.
2. Description of the Related Art
Well known in the art of integrated circuit manufacture is the use of radio frequency excitation to produce reactive and non-reactive plasmas which assist in processing integrated circuit layers. The plasmas which assist in processing integrated circuit layers may be directed towards several aspects of integrated circuit layer fabrication. Plasmas may be employed to assist in integrated circuit layer fabrication processes including but not limited to integrated circuit layer formation processes, integrated circuit layer removal processes and integrated circuit layer modification processes. The types of integrated circuit layers whose processing may be assisted through the use of radio frequency plasmas include but are not limited to conductor layers, insulator layers, semiconductor layers and photo-active layers.
Although the use radio frequency excitation to produce plasmas which have applications within virtually every aspect of integrated circuit layer fabrication have become quite common in the art, such plasmas are not without problems. In particular, one of the more troubling problems resulting from plasma assisted processing of integrated circuit layers is the formation of contaminant particles within plasma assisted process reactor chambers and the deposition of those contaminant particles upon the surfaces of integrated circuit layers which are processed by plasmas contained within those chambers. The contaminant particles may be generated from several sources, including but not limited to the materials from which is formed the plasma and the materials from which is formed the reactor chamber within which is contained the plasma. When deposited upon the integrated circuit layers for whose processing the plasma is intended, the particles resulting from these materials assist in forming defects which impede production of fully functional and reliable integrated circuits.
Several aspects of the dynamics of contaminant particle formation and deposition within radio frequency plasma assisted integrated circuit layer fabrication processes and process reactor chambers are known in the art. For example, it is known that plasma induced electrostatic forces are likely to play significant roles in contaminant particle deposition upon integrated circuit layers exposed to a plasma within a plasma process reactor chamber. Alternatively, it is also known that non-electrostatic forces, such as temperature gradient forces, fluid dynamic drag forces and gravitational forces are likely to play more significant roles in contaminant particle deposition upon integrated circuit layers within process reactor chambers where a radio frequency plasma is absent. It is thus towards the control of contaminant particles within radio frequency plasma assisted integrated circuit layer processing chambers through methods that derive from an understanding of particle formation and deposition dynamics within those chambers that the present invention is directed.
Methods through which various features of plasma assisted integrated circuit layer processing methods may be influenced through understanding of the technical principles upon which those processes are based are known in the art. For example, Jain et al., in U.S. Pat. 5,403,780 describe a method for enhancing the planarization etch-back profile, the stability and the reliability of silicon oxide insulator layers formed through plasma assisted etching processes. The disclosed method employs a composite silicon oxide insulator layer, portions of which are formed with a silicon content tailored to provide the desired planarization, stability and reliability characteristics of the composite silicon oxide insulator layer.
Desirable in the art are methods whereby a fundamental understanding of particle generation and deposition phenomena are analogously employed in defining plasma assisted processes through which contaminant particulate deposition upon integrated circuit layers within plasma assisted process reactor chambers is limited. Highly desirable is methodology which is generally applicable to a wide variety of plasma assisted processes and plasma assisted process reactor chambers.